Any replicator should be able to work with either format. As a former replicator, I would always prefer to receive a DDP imagae as i can basically bring that right into an LBR (laser beam recorder) for glass mastering without having to do any conversion of supplied files. If you are to create DDP images, I would confirm with the glass mastering house (or replicator) what DDP format they require. I agree with Danny that you should create a working disc as well and label them properly. The replicator may end ups using that if it passes analysis and is written in the proper format.